Dai-Guard - Vol. 5: In the Red (DVD, 2003)

12 years ago, a strange enemy from another dimension arrived and destroyed Tokyo who was almost completely immune to traditional weapons. To combat this alien menace, the government built the giant robot Dai-Guard. Now, years of peace have made Dai-Guard a useless anomaly, and the government foists the robot off on the 21st Security Corporation, a civilian corporation. In these episodes, the Dai-Guard pilots find themselves getting it almost as bad from their bosses as they are from aliens. Fortunately, the Dai-Guard pilots are determined to be heroes and set out to defend the Earth until the last alien falls.